Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, impulsiveness, and hyperactivity. It is estimated that 3% of adults worldwide are affected. Dementia is not a specific disease but is rather a general term for the impaired ability to remember, think, or make decisions that interfere with doing everyday activities.
Using national registries, the researchers linked the participants to more than 5 million biological relatives — including parents, grandparents, uncles, and aunts — and looked into whether they developed dementia later in life. People with ADHD had a 34% higher risk of developing dementia than those who did not have the disorder. Those with ADHD had a 55% greater chance of being diagnosed with Alzheimer’s disease, the most common type of dementia.
A large study at Sweden’s Karolinska Institutet discovered a link between ADHD and dementia across generations. The study, published in Alzheimer’s & Dementia, found that parents and grandparents of people with ADHD were more likely to develop dementia than those with children and grandchildren who did not have ADHD.
“The findings suggest that the association between ADHD and dementia is due to shared genetic and/or environmental factors.” “We now need more research to understand the underlying mechanisms,” says the study’s first author, Le Zhang, a Ph.D. student at Karolinska Institutet’s Department of Medical Epidemiology and Biostatistics.
There’s a link between attention-deficit/hyperactivity disorder (ADHD) and dementia across generations, according to a new study. The risk of being diagnosed with Alzheimer’s, the most common type of dementia, was 55% higher for those with ADHD.
The number of new ADHD diagnoses has risen dramatically in recent decades, owing to increased awareness and understanding of the disorder. However, because the diagnosis is still relatively new, there have only been a few small studies on the development of dementia in people with ADHD, with often contradictory results.
The current study sought to address this by examining the extent to which older generations of ADHD patients were diagnosed with dementia. The study included over two million people born in Sweden between 1980 and 2001, with approximately 3.2 percent diagnosed with ADHD. Using national registries, the researchers linked these people to over five million biological relatives, including parents, grandparents, uncles, and aunts, and looked into how much dementia these relatives had.
The researchers discovered that parents of ADHD children had a 34% higher risk of dementia than parents of non-ADHD children. The risk of Alzheimer’s disease, the most common type of dementia, was found to be 55% higher in parents of ADHD patients. Individuals with ADHD were more likely to have parents who had early-onset dementia than those who had late-onset dementia.
The researchers note that the parent cohort’s absolute risk of dementia was low; only 0.17 percent of the parents were diagnosed with dementia during the follow-up period. The association was weaker for second-degree relatives of people with ADHD, such as grandparents, uncles, and aunts. Grandparents of ADHD patients, for example, had a 10% higher risk of dementia than grandparents of non-ADHD patients.
While the study was unable to establish a cause-and-effect relationship, the researchers presented several potential explanations that can be investigated further in future research. “One could imagine that there are undiscovered genetic variants that contribute to both traits, or family-wide environmental risk factors, such as socioeconomic status, that may have an impact on the association,” says Zheng Chang, the study’s last author and researcher at Karolinska Institutet’s Department of Medical Epidemiology and Biostatistics.
“Another possible explanation is that ADHD raises the risk of physical health problems, which raises the risk of dementia.” According to a study news release, researchers are unable to pinpoint a “cause-and-effect relationship” between dementia and ADHD at this time, but offer explanations that may be investigated in future studies.
In the release, Zheng Chang, one of the study’s authors and a researcher at Karolinska Institutet’s Department of Medical Epidemiology and Biostatistics, said, “One could imagine that there are undiscovered genetic variants that contribute to both traits, or family-wide environmental risk factors, such as socioeconomic status, that may have an impact on the association.”
“The findings imply that the association between ADHD and dementia is caused by shared genetic and/or environmental factors. More research is needed to understand the underlying mechanisms “Zhang stated in a press release.